1. Field of the Invention
The present invention relates to a wireless network, and in particular, to a wireless network having multi-rate channels.
2. Description of the Related Technology
Wireless networks typically include a plurality of wireless stations. When a wireless network includes three or more wireless stations, the wireless network needs to manage the transmission of data and/or control signals between the wireless stations.
Certain wireless networks allocate time for data and/or control signals between wireless stations therein, using a so-called contention-based protocol (CBP). A contention-based protocol is a communications protocol that allows wireless stations to use the same radio channel without pre-coordination.
According to the United States Federal Communication Commission rules, a contention-based protocol is defined as “a protocol that allows multiple users to share the same spectrum by defining the events that must occur when two or more transmitters attempt to simultaneously access the same channel and establishing rules by which a transmitter provides reasonable opportunities for other transmitters to operate. Such a protocol may consist of procedures for initiating new transmissions, procedures for determining the state of the channel (available or unavailable), and procedures for managing retransmissions in the event of a busy channel.” The “listen before talk” operating procedure in IEEE 802.11 is the most well-known contention-based protocol.
Some wireless networks use multi-rate channels for the transmission of data and/or control signals between wireless stations therein. Such wireless networks may use a contention-based protocol for allocating time for data and/or control signal transmission. Such wireless networks, however, may have a problem in using a contention-based protocol due to the characteristics of the multi-rate channels. Therefore, there is a need for a scheme suitable for wireless networks using multi-rate channels.